Haunted House Update

So last night I was in the living room, headphones plugged into the laptop watching some British TV shows we don't get in America.  My partner was at the computer in the dining room, also with headphones on and listening to something on the Internet.  The living and dining rooms are actually one large room, by the way.  Anyway, I heard a loud crash come from his general direction.  First thought:  he knocked a chair over or maybe fell (the floors are uncarpeted hardwood so falling stuff is loud).  He heard the same noise but thought I'd fallen out of my chair. 

We looked at each other questioningly, took off our respective headphones, and said about what you'd expect.  "Did you hear that?"  "What was it?"  "I thought you fell over."  "I thought you did."  A few more seconds of staring and then the inspection.  No one was knocking at either door.  Nothing had fallen.  I checked the basement (the rabbits were not agitated like they usually are if there's a loud noise) and everything was fine upstairs.  So...

Yep.  It's a strange one. Could be the spirit sharing my house saw us both glued to computers, headphones doffed, and simply wanted some attention.  Or maybe she tripped and fell.  That would be interesting...a clumsy ghost.